Earth, Moon, and Sun Study Guide 4.8
Vocabulary
axis – the imaginary line on which the Earth spins
Apollo Missions – The Apollo program designed to land humans on the Moon and bring
them safely back to Earth
Earth – the third planet from the sun; supports life (93 million miles away from the sun)
lunar eclipse - when the Earth moves between the sun and the moon (A shadow is cast on
the moon.)
moon – a small, rocky, natural satellite that revolves around the Earth (1/4 the size of the
Earth)
NASA – National Aeronautics and Space Administration
orbit – the path an object in space follows as it revolves around another object
phases of the moon – a pattern that repeats itself every 29 1/3 days
revolution – one full orbit (circle) around another object
rotation – the spinning motion of an object on its axis (like a top)
solar eclipse - when the moon moves between the Earth and the sun (A shadow is cast on
the Earth.)
sun – a yellow, average-size star at the center of our solar system that produces heat and
light (110 times the diameter of the Earth)
waning – a term used to describe the moon reflecting less light (seems to grow smaller)
waxing – a term used to describe the moon reflecting more light (seems to grow larger)
Phases of the Moon
Sun’s Rays
The Moon
• The moon is a small rocky satellite, having about one-quarter the diameter of the Earth
and one-eightieth of
its mass.
• The moon is approximately 4.6 billion years old.
• The moon has little or no atmosphere and no oxygen.
• The moon has no water, wind, clouds, weather, or life.
• You would weigh one-sixth of your Earth weight on the moon.
• The moon is pitted with large craters.
• The moon’s surface is very hot during its days and freezing during its nights.
• The distance from the moon to the Earth is 240,000 miles.
• The NASA Apollo missions added greatly to our understanding of the moon.
The Sun
• The sun is 1.4 million kilometers (870,000 miles) in diameter. It is about 110 times
the diameter of the Earth.
• The sun is a large globe of hot gas with a surface temperature of 10,000,000°
Celsius.
• The distance between the Earth and the sun is 150 million kilometers (93 million miles).
• The sun is made mostly of hydrogen. It has enough hydrogen to stay shining for about 4
billion years.
• The sun is an average-size star. It is just like the others in the sky, except the sun is
much closer to us.
• The sun is approximately 4.6 billion years old.
Earth
• The Earth is the 3rd planet from the Sun.
• The Earth is one of the 4 rocky inner planets.
• It has large amounts of life-supporting water and an oxygen-rich atmosphere.
• It is a geologically active planet with a surface that is constantly changing.
• The Earth’s protective atmosphere blocks out most of the sun’s damaging rays.
Historial Contributions
Aristotle
Aristotle was born in Greece. He believed that the Earth was a sphere and that the
universe was spherical.
Ptolemy
Ptolemy was an Egyptian geographer, astronomer, and mathematician who
believed that the planets and sun orbited the earth. He agreed with Aristotle that
the solar system was an Earth-centered model.
Nicolaus Copernicus
Copernicus was a Polish astronomer who theorized that the planets revolved
around the sun. He determined the size of the sun and moon and the
distances of the sun and moon from the Earth.
Galilei Galileo
Galileo was an Italian scientist who was the first to use a telescope for
astronomy. He discovered the rings of Saturn and the mountains and craters on
the moon. He supported Copernicus’ theory that everything revolved around the
sun (sun-centered model).
Big Idea Questions
• Describe how Earth and its moon move. Does the sun move?
• Describe two ways Earth moves.
• Describe the characteristics of the sun. Be sure to include its approximate size, color,
age, and overall composition.
• What causes the seasons on Earth?
• Why does the Southern Hemisphere of Earth have summer when the Northern
Hemisphere is having winter?
• What causes the phases of the moon?
• Explain the sequence of the eight phases of the moon.
• Explain the difference between a waxing moon and a waning moon phase.
• How are we able to see the moon on clear nights? Can the moon produce its own light?
• If you wanted to show a younger student the size relationship between Earth, its moon,
and the sun, what three objects could you use? How could you demonstrate the distance
relationship between them?
• How are the surfaces of Earth, the moon, and the sun different? How are they alike?
• How do you think the moon would be different if it had liquid water?
• Aristotle and Ptolemy had the same thoughts about our solar system. What did they
think about the organization of the solar system?
• Copernicus and Galileo agreed with each other, but disagreed with Aristotle and
Ptolemy. What did they believe about the solar system?
• Which two men were correct about the organization of our solar system?
• How has NASA missions helped us better understand the moon?
• Do you think we will ever make new discoveries about the moon? Why or why not?